In the world, the carrying capacity for humans is limited. History holds all things in the balance, including large hopes and short lives. When Albert Schweitzer walked into the jungle, bless his heart, he carried antibacterials and a potent, altogether new conviction that no one should die young. He meant to save every child, thinking Africa would then learn how to have fewer children. But when families have spent a million years making nine in the hope of saving one, they cannot stop making nine. Culture is a slingshot moved by the force of its past. When the strap lets go, what flies forward will not be family planning, it will be the small, hard head of a child. Overpopulation has deforested three-quarters of Africa, yielding drought, famine, and the probable extinction of all animals most beloved by children and zoos.The competition for resources intensifies, and burgeoning tribes itch to kill each other. For every life saved by vaccination or food relief, one is lost to starvation or war. Poor Africa. No other continent has endured such an unspeakably bizarre combination of foreign thievery and foreign goodwill. Out of sympathy for the Devil and Africa, I left the healing profession. I became a witch doctor. My church is the Great Rift Valley that lies along the eastern boundary of Congo. I do not go there. I merely study the congregation.

This is the story I believe in: When God was a child, the Rift Valley cradled a caldron of bare necessities, and out of it walked the first humans upright on two legs. With their hands free, they took up tools and beat from the bush their own food and shelter and their own fine business of right and wrong. They made voodoo, the earth’s oldest religion. They engaged a powerful affinity with their habitat and their food chain. They worshiped everything living and everything dead, for voodoo embraces death as its company, not its enemy. It honors the balance between loss and salvation. This is what Nelson tried to explain to me once, while we scraped manure from the chicken coop. I could not understand how muntu could refer to a living person or a dead one with equal precision, but Nelson just shrugged.”All that is being here.”

God is everything, then. God is a virus. Believe that, when you get a cold. God is an ant. Believe that, too, for driver ants are possessed, collectively, of the size and influence of a Biblical plague. They pass through forest and valley in columns a hundred meters across and many miles long, eating their way across Africa. Animal an000000d vegetable they take, mineral they leave behind. This is what we learned in Kilanga: move out of the way and praise God for the housecleaning. In a few days the dark brigade will have passed on through-those ants can’t stop moving. You return to find your houses combed spotless of spoiled crumbs, your bedding free of lice, your woodlots cleansed of night soil, your hen coops rid of chicken mites. If by chance a baby was left behind in a crib, or a leopard in a cage, it would be a skeleton without marrow, clean as a whistle. But for those prepared to move aside for a larger passage, it works. Loss and salvation.

Africa has a thousand ways of cleansing itself. Driver ants, Ebola virus, acquired immune deficiency syndrome: all these are brooms devised by nature to sweep a small clearing very well. Not one of them can cross a river by itself. And none can survive past the death of its host. A parasite of humans that extinguished us altogether, you see, would quickly be laid to rest in human graves. So the race between predator and prey remains exquisitely neck and neck.

As a teenager reading African parasitology books in the medical library, I was boggled by the array of creatures equipped to take root upon a human body. I’m boggled still, but with a finer appreciation for the partnership. Back then I was still a bit appalled that God would set down his barefoot boy and girl dollies into an Eden where, presumably, He had just turned loose elephantiasis and microbes that eat the human cornea. Now I understand, God is not just rooting for the dollies. We and our vermin all blossomed together out of the same humid soil in the Great Rift Valley, and so far no one is really winning. Five million years is a long partnership. If you could for a moment rise up out of your own beloved skin and appraise ant, human, and virus as equally resourceful beings, you might admire the accord they have all struck in Africa.

Back in your skin, of course, you’ll shriek for a cure. But remember: air travel, roads, cities, prostitution, the congregation of people for efficient commerce-these are gifts of godspeed to the virus. Gifts of the foreign magi, brought from afar. In the service of saving Africa’s babies and extracting its mineral soul, the West has built a path to its own door and thrown it wide for the plague.

A toad can die of light! Death is the common right of toads and men. Why swagger, then? My colleagues accuse me of cynicism, but I am simply a victim of poetry. I have committed to memory the common rights of toads and men. I could not swagger if I tried. I don’t have the legs for it.

My work is to discover the life histories of viruses, and I seem to be very good at it. I don’t think of the viruses as my work, actually. I think of them as my relations. I don’t have cats or children, I have viruses. I visit them daily in their spacious glass dishes, and like any good mother I cajole, I celebrate when they reproduce, and I take special note when they behave oddly. I think about them when I am not with them. I have made important discoveries about the AIDS and Ebola viruses. As a consequence, I must sometimes appear at public functions where I am lauded as a saviour of the public health. This startles me. I am nothing of the kind. Certainly I’m no mad exterminator bent on killing devil microbes; on the contrary, I admire them. That is the secret of my success.

My life is satisfying and ordinary. I work a great deal, and visit my mother on Sanderling Island once a month. I enjoy my time there, which we mostly pass without speaking. Mother lets me be. We take long walks on the beach, where she watches those namesake shore-birds, the sanderlings, leaving no stone unturned. Sometimes in mid-January when she seems restless we’ll take the ferry and drive up the coast highway, passing through the miles of flat, uninhabited palmetto scrub and the occasional stick shack, where old, dark women sit weaving beautiful sweetgrass baskets. Late in the evening we will sometimes pull into the dirt parking lot of a clapboard praise house and listen to old, dark Gullah hymns rising out the windows. We never go inside. We know our place. Mother keeps her head turned the “whole time toward Africa, with her eye on the ocean, as if she expects it might suddenly drain away.

But on most of my visits we go nowhere. We sit on her porch, or I watch while she works her small jungle, snapping off dead leaves, forking rotted manure into her camellias, talking under her breath. Her apartment is the ground floor of one of those century-old brick boxes with earthquake bolts, remarkable pieces of giant hardware that run right through the building from east to west, capped off on the outside with iron washers the size of end tables. I think of them as running through Mother too. It would take something on this order, really, to hold her together.

She inhabits her world, waiting for forgiveness, while her children are planted in or upon the four different nations that have claimed us. “Lock, stock, and barrel,” she calls us. Rachel is clearly the one with locks on every possible route to defenestration. And Leah barrels forward, setting everything straight. So I am the one who quietly takes stock, I suppose. Believing in all things equally. Believing fundamentally in the right of a plant or a virus to rule the earth. Mother says I have no heart for my own kind. She doesn’t know. I have too much. I know what we have done, and what we deserve.